The invention relates to a system for distribution of high quality electrical power to a plurality of loads from an AC electrical power distribution network.
An increasingly large number of equipment items, for example in the computer and electronic fields, require a high quality electrical power supply, i.e. essentially a power supply that is always available, well-suited to the equipment and insensitive to disturbances.
The availability problem is at present generally solved by means of an Uninterruptible Power Supply (UPS) connected between the AC mains (50 Hz or 60 Hz) and the equipment involved. Power is distributed to the equipment by the UPS in the form of alternating current of preset frequency and amplitude, generally of the same order as those of the initial power network. The UPS comprises a battery, normally charged by the network, which takes over in the event of network outages for a limited time, about half an hour for example. In the event of network outages of long duration, an electrical generating set or a second power network can, in back-up configuration, be connected to the input of the UPS instead of the network which has become unavailable.
To avoid the costly and cumbersome use of one UPS per item of equipment, a single UPS of suitable power is often provided, associated with a plurality of equipment, or loads, connected in parallel to the output of the UPS. If the power supplied is available, its quality is not always sufficient. Indeed, in this configuration some loads can create disturbances affecting the loads connected in parallel. These reciprocal disturbances can be limited by the use, line-side of each of the equipment items, of harmonic filters and/or isolating transformers, which again makes the installation costly and complex.